JPS645583B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates generally to novel polyols and processes for making polyols, and in particular to mono-, di-, tri-, and tetra- -, penta- and hexa-methylol compounds. The reaction of formaldehyde and acetone has already been characterized. In 1911,
USP989993 (Bayer) produces methylolacetone by condensation of acetone and formaldehyde in the presence of a dilute alkali: USP2387933 (British Celanese)
The use of an aqueous solvent system and maintenance of a pH range of 8.5-9.5 increased product yield and reduced by-product formation. Again, the product was monomethylolacetone. Manufacture of dimethylolacetone USP1955060
(IG Falben Industrie AG). Dimethylolacetone exists in asymmetric or symmetric isomers: The production of dimethylolacetone by the conventional method is
The reaction involved formaldehyde and acetone using a strong inorganic alkali catalyst that maintains the pH above 10.0. The following equation is believed to explain the role of strong alkaline catalysts in the methylolation of acetone: 1 Abstraction of hydrogen atoms from α-carbon atoms: 2 Reaction between carbane ion and formaldehyde: 3 Regeneration of catalyst Theoretically, the above mechanism can be repeated until up to 3 moles of formaldehyde are substituted for each alpha carbon atom of acetone. However, when each additional hydrogen atom attached to the alpha carbon atom is replaced by a methylol group, the reaction conditions become more severe. As mentioned above, in the prior art, methylol-substituted acetone was formed by the reaction of the acetone carbane ion with formaldehyde; when the alpha carbon atom is more highly substituted, a stronger alkali is required for the formation of the carbane ion. It is. Therefore, hitherto only mono- and dimethylolacetone were known. With this invention it has surprisingly been found that in addition to mono- and di-methylol ketones, tri- and tetra-methylol acetones or ketones can be obtained. As recognized in the prior art, the first hydrogen atom retained on the alpha carbon atom is easily replaced. However, further substitution is difficult as shown in the following equation: In particular, the remaining hydrogen atoms on the alpha carbon atom are very difficult to extract with an alkali catalyst. Furthermore, as the alkaline strength increases, by-product formation becomes more abundant. In fact, by-products such as diacetone alcohol, pinacol, methyl vinyl ether and various cyclic ethers are formed in large quantities with increasing alkaline strength. An important feature of this invention is the discovery that catalysis of amines, such as tertiary amines, is effective in achieving the replacement of 1 to 6 molecules of formaldehyde with each molecule of ketone or acetone. In this system, the reaction PH is kept moderately alkaline, ie below PH10, and by-product formation is kept to a minimum. Although the reaction mechanism is not completely clear,
It is believed that the tertiary amine catalyst forms a complex with the hydrogen atom attached to the alpha carbon atom of the ketone or acetone. Thus, up to six methylol groups replace each molecule of ketone. It was previously thought that a product with this characteristic could not be produced in the pH range below 10. According to the processing methods and conditions used in the practice of this invention, side reactions can be minimally or completely eliminated. The mechanism for catalyzing formaldehyde substitution using a tertiary amine catalyst is shown as follows: (In the formula, R is other than hydrogen and the three Rs may be different.) Formaldehyde molecules are also partially polarized due to the lone pair of their carbonyl oxygens: The various partial charges are the partial positive charge formaldehyde carbon and the partial negative charge α of acetone due to the following mechanism.
Promote reaction with carbon: Thus, the tertiary amine helps polarize the alpha carbon of acetone and facilitates covalent bonding of the reactants for subsequent covalent bonding. Shown below is the structure of the product formed in the practice of this invention in the reaction of acetone and formaldehyde catalyzed by a trisubstituted amine.

【table】

[Table] Tetramethylol-substituted acetone was obtained by the following method, which is illustrated in the following examples, but is not limited thereto. Example 1 In a reactor equipped with a heater, a cooler and a stirrer, the following were added: Acetone 7.5 mol Formaldehyde 30 mol Triethylamine 0.75 mol The above solution containing 1/3 triethylamine was stirred well and heated to 50°C. and held at 50°C for 1 hour.
Add the remaining 2/3 of triethylamine and heat at atmospheric pressure.
Refluxed for 45 minutes and cooled to room temperature. The resulting product had a solids content of 53%, a viscosity of 32 cps, a pH of 8.75, and was infinitely dilutable in water. The final product, containing 2% unreacted formaldehyde, had a specific gravity of 1.1340. The NMR data of this final product was as follows.

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【table】

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Table: Tri-, penta- and hexamethylol substitution products are obtained using appropriate substantially stoichiometric concentrations of both reactants. The acetone used need not be anhydrous; experiments have demonstrated that the reaction mixture can contain as much as 50% water or more. Paraformaldehyde, 65%, 55%, 45 or
Various forms of formaldehyde can be effectively used, including a standard product of 37% methanol-containing polymerization-inhibited formaldehyde solution or any other suitable formaldehyde donor. The preferred basic catalyst for this reaction of ketones and aldehydes is triethylamine.
Other functionally equivalent compounds (trisubstituted amines)
is also used. It has been discovered by this invention that the basic or alkaline nature of organic catalysts is more efficient in driving reactions to completion than inorganic alkaline agents.
The use of triethylamine makes the reaction highly exothermic and reduces 95% of the formaldehyde consumed.
or higher yield. In contrast, basic catalysts such as caustic soda, barium hydroxide, calcium hydroxide, lithium hydroxide, alkali metal and alkaline earth metal carbonates, or primary or secondary amines such as ammonia or diethylamine are effective. However, interfering amine catalysts, i.e. catalysts that are basic in character and prevented from reacting with the carbonyl group of the ketone, are It is an important and unexpected discovery of this invention that it is extremely useful for inducing ketone-aldehyde reactions to provide desired end products. Catalysts contemplated by this invention are not limited to triethylamine alone, but include any tertiary amine having alkyl, aryl or combined aryl-alkyl substituents. Representative examples of tertiary amines include n-methylmorpholine, dimethylaniline, triethylamine, N,N-dimethyltoluidine and methyldiethylamine. The reaction of acetone and formaldehyde contacted with sufficient triethylamine to maintain a minimum pH of 8.6 can be completed in 20 minutes to about 4 hours, depending on the temperature of the system. The useful temperature range is
It was found to be in the range of about 40°C to about 120°C. As the addition of formaldehyde progresses,
As the temperature of the reactants increases, the reaction temperature can be gradually increased to complete the reaction more rapidly. Although this reaction has been described with respect to acetone and formaldehyde as reactants, those skilled in the art will be aware of other ketones and other methylol groups (-CH ₂ OH).
It is understood that any source can be used, and with the teachings of this invention modifications of this reaction can be carried out without particular inventiveness and without the need for much experimentation. Example 2 The tetramethylol product of Example 1 was mixed with phenol formaldehyde resol at 1:4 solids content of tetramethylol acetone to phenol-formaldehyde: Phenol-formaldehyde (67% solids)
2400 g Tetramethylolacetone (53% solids) 800 g This mixture was dehydrated to obtain a system with the following properties: Viscosity 330 cps Specific gravity 1.2072 Stroke cure 179 seconds (150°C) Spontaneous gelation 522 seconds (135°C) ) PH 8.5 ASTM Solids 65% (135°C) The practicality of the resulting mixture was found to be twofold. Tetramethylolacetone replaces the usual conventional methanol solvent required to solubilize the phenol-formaldehyde resol. Furthermore, tetramethylolacetone not only serves as a solvent for the phenol-formaldehyde system, but instead of being distilled off like methanol, it reacts with the system itself and becomes a constituent component of the system. The use of tetramethylolacetone rather than methanol as a solvent provides a reaction system that can be further diluted with water, depending on the solubility of the drug being polymerized. This novel aspect of the invention eliminates the need for the use of conventional volatile diluents or solvents. The practical effect of this innovation is to greatly reduce the risk of fire and effectively prevent air pollution. The methylol and polymethylol ketones of this invention have a wide range of uses: 1. Phenol-formaldehyde resins, melamine-formaldehyde resins, urea-formaldehyde resins, xylenol-formaldehyde resins, naphthol-formaldehyde resins, aniline-formaldehyde resins. Formaldehyde resin, dicyandiamide-formaldehyde resin, furfuryl alcohol-formaldehyde resin, furfuraldehyde-phenol resin, cresol-formaldehyde resin, diphenol oxide-formaldehyde resin, bisphenol-formaldehyde resin, benzoguanimine-formaldehyde resin, quinone-formaldehyde resin, Hydroquinone-formaldehyde resin, furan-formaldehyde resin, epoxy resin,
Chemically reactive, copolymerizable diluent for use with nylon resins, polyester resins, polyvinyl alcohol resins, resorcinol-formaldehyde resins, aromatic and aliphatic substituted phenol-formaldehyde resins and silicone resins. 2 Coreactant or curing agent for epoxy resin. 3 Chemically reactive polyols particularly useful with isocyanate compounds to form urethane coatings, adhesives or foams, and low content of ionic species for tertiary amine catalysts are compatible with isocyanate compounds. ing. 4. As reactants with organic acids or acid anhydrides, polyester resins useful as coatings, molding compounds, adhesives or foams are formed. 5 Alternatives to polyols such as pentaerythritol, trimethylolpropane, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol or polyethylene glycol. 6 In alkyd resins, acetone-formaldehyde resins are an alternative to glycerin or polyols for coatings and binders. 7. Combined with phosphorus, sulfur, halogen or nitrogen-containing substances as flame retardants. The polyols of this invention can be copolymerized or reacted with crosslinking agents such as isocyanates, blocked isocyanates, polymerized isocyanates, organic and inorganic acids, acid anhydrides, amines and amides, and hydroxy-containing polyols such as alcohols, glycols and polyols. Can react with substances as well as polymerizable agents that can react with alcoholic hydrogen.

Claims (1)

[Scope of Claims] 1 Ketones having 3 to 6 hydrogen atoms bonded to an α carbon atom, the group consisting of dialiphatic ketones, diaromatic ketones, aliphatic-aromatic substituted ketones, and mixtures thereof. and formaldehyde or a formaldehyde generator or donor in the presence of a tri-substituted alkyl amine catalyst and in the absence of a solid phase catalyst in an alkaline reaction mixture having a pH of about 10 or less to form an alpha carbon. A method for producing polymethylolketone, which comprises forming a polymethylolketone having 3 to 6 methylol groups bonded to an atom. 2. The method according to claim 1, wherein the ketone is acetone. 3. The method of claim 1, wherein the trisubstituted alkylamine is triethylamine. 4. The method of claim 1, wherein the trisubstituted alkylamine is selected from the group consisting of N-methylmorpholine, dimethylaniline, trimethylamine, N,N-dimethyltoluidine or methyldiethylamine.